Pen



FIG. 1 is a top, rear and left side perspective view of the pen;

FIG. 2 is a left side elevational view, the right side elevational view being a mirror image thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevational view thereof; and,

FIG. 6 is a rear elevational view thereof. 

The ornamental design for a pen, as shown and described. 